Smooth-leaved Elm
The Smooth-leaved Elm (Ulmus minor subsp. minor), is a subspecies of the Field Elm native to southern Europe and Asia Minor including Iran. Description A deciduous tree that once commonly grew < 35 m tall, its Latin synonym carpinifolia alluding to the superficial similarity of the leaves to those of Hornbeam Carpinus sp., while the common names contrast the smooth upper surface and narrowness of the leaves with those of the Wych Elm, which are rough and broad. The apetalous perfect wind-pollinated flowers, and fruit (samarae) are very similar to those of the species. Pests and diseases Although the Smooth-leafed Elm is generally susceptible to Dutch elm disease, it is genetically a highly variable tree and it is possible some specimens survive in the UK owing to an innately high level of resistance (see Cultivation). Research currently (2009) in hand by Cemagref at Le Pepiniére forestiére de l’Etat, Guémené-Penfao, France, should confirm this. However, all Smooth-leafed Elm varieties are believed to have been introduced into Britain from central and southern Europe during the Bronze Age, and some being beyond their natural climates and environments may be growing slowly and thus producing smaller springwood vessels restrictive to the Ophiostoma fungus. Good performance in the field may also be owing to resistance to bark beetle feeding or breeding. Moreover, several types of this subspecies also have very pendulous twigs when mature, a factor which could also make them unattractive to foraging beetles. Of over twenty mature elms of various species, including hybrids and cultivars, in the elm collection of the Royal Botanic Garden Edinburgh in 1990, only four specimens survive in 2010: two of them are U. minor subsp. minor types with pendulous twigs (the other two are Ulmus glabra 'Exoniensis' and Ulmus pumila var. arborea). The subspecies has a moderate to high susceptibility to the elm leaf beetle Xanthogaleruca luteola, and a moderate susceptibility to Elm Yellows. Notable trees The largest recorded tree in the UK grew at Amwell, Herts., measuring 40 m in height and 228 cm d.b.h. in 1911. Another famous specimen was the great elm that towered above its two siblings at the bottom of Long Melford Green, Long Melford, Suffolk, till the group succumbed to disease in 1978. The three "were survivors of a former clone of at least nine elms, one dating from 1757". The Long Melford elms were painted in 1940 by the watercolourist S. R. Badmin in his 'Long Melford Green on a Frosty Morning', now in the Victoria and Albert Museum. The largest known surviving trees are at East Coker, Somerset (30 m high, 95 cm d.b.h.), Termitts Farm near Hatfield Peverel, Essex (25 m high, 145 d.b.h.), Scrub Wood near Little Baddow, Essex (30 m high), and Melchbourne, Bedfordshire, (147 cm d.b.h.). A large old coppiced U. minor subsp. minor, with an 18-foot girth at coppice-level, stands 2010 at the edge of Sturt Copse beside the Roman villa at North Leigh, Oxfordshire. It retains its dense canopy of dark green leaves late into autumn, making it stand out against the yellowing wych elms in the area. Category:Trees Category:Deciduous Category:Plants